The story of the Yelkouan Shearwaters' annual pilgrimage to Malta begins in November. Ten per cent of the world's population of the species come back to the rocky cliffs of the Maltese Islands to look for a nesting site in which to raise their chicks in the coming spring. But this year was to be different for some of the birds returning to find a burrow in the cliffs. Their migration back to the islands coincided with the beginning of the EU LIFE Yelkouan Shearwater Project, designed to protect them. For birds returning to Rdum tal-Madonna, the project site, there were changes afoot!
On the face of it, everything looked the same for the birds. As usual, around nightfall, they swirled around the cliffs of Rdum tal-Madonna and competed with one another for the safest burrow, deep in the cliffs and as inaccessible as possible. Yelkouan shearwaters (Puffinus yelkouan) prefer to use the same burrow again and will evict intruders if necessary. Once those battles had been fought, the birds spent their time "chasing the wind" (the meaning of the Turkish word "yelkouan"). They fished offshore until it was time to meet their mate from previous years or in the case of younger birds or widows, to form a bond with a new bird. By February, the birds were ready to mate and begin the process of laying their eggs. And that's where the influence of the Yelkouan Shearwater project would first be felt by the shearwaters.
Normally, once the birds have laid their single, chalky-white egg, they are faced with a serious problem; rats. These voracious predators are attracted to sites like Rdum tal-Madonna by the rubbish left behind by campers and their BBQs. The rats multiply and for some of them, shearwaters eggs and chicks become the dish of the day. For many years now, rats have been affecting the population of this internationally protected species and devouring young birds. One of the first actions of the project therefore was to set up an extensive grid of baited rat eradication stations. After a lot of hard work, this wiped out the rat population. Now the Site Warden has been doing a regular patrol to keep rat numbers down using a permanent cordon of stations to prevent any incoming rats from getting to the cliffs where the birds breed.
This meant that for the first time in a long time, there were no broken eggshells or half eaten chicks on the cliffs when researcher John J Borg from the National Museum of Natural History (Heritage Malta) descended the cliffs by abseil to start monitoring the nests. The nesting areas were also free of rat dropping. John started to hear chicks in some of the burrows, proving that they had not fallen victim to rats. However, the team remain vigilant; the continuing success of the rat eradication and the survival of the chicks depend on visitors to the site taking their rubbish away with them.
|John J Borg of Heritage Malta
||Dr.Andre Raine of BirdLife Malta
Once the birds had managed to evade their rodent predators, the next challenge for them during the breeding season was to incubate the egg and find food. During the egg laying period, both parents take turns to incubate, remaining deep in their burrows for up to a week at a time while their partners go fishing. But by late May, the chicks were hatching and the trips for fishing became shorter and more frequent as the parents struggled to keep up with the demands of another hungry beak. And here the birds found another change..
On the Cliffs
During the egg laying and chick hatching period, the project team needed to find out more about pair fidelity, burrow occupation and breeding success.. So once a week, as the birds flew back in the darkness and aimed straight for their burrows, researchers John Borg and Dr. Andre Raine (BirdLife Malta's Conservation Manager) and their team were waiting to monitor them. The team co-ordinated their actions to make sure this monitoring work was quick and efficient. Each bird was ringed (or in the case of birds already ringed, the number was noted), weighed and measured then released straight away with no ill effects to feed its chick.
Without the rats to bother them, the chicks grew fat and fluffy and the adult birds continued to come and go, sometimes meeting in the nest overnight for a few hours, but always departing before the first light of day. It was one of the real pleasures of the job for the team to here the squeaks and coos of the chick as it begged for food inside the cliff while the adults deeper contact calls echoed in the cavities and flying birds called out at sea.
Now the focus of the monitoring programme started to change. John and Andre needed to find out more than just how many chicks were surviving to how many pairs. In order to protect the birds effectively at sea, they needed to find out exactly where they go fishing for food for their young. This required some cutting edge technology, never before attempted with Yelkouan Shearwaters in Malta and rather a lot of patience!
|Yelkouan Shearwater, copyright John J Borg
||The shearwater after data logging
The team selected a strong healthy bird which had a chick and a partner. Dr. Raine and John Borg then fitted this bird with a data logger, an electronic tracking device on its back which would record its position every two seconds while out at sea. Then they had to wait for the bird to come back... and wait.... and wait. The shearwaters' habit of coming in only at night is also linked to the phase of the moon (a bright moon rising early means the shearwaters returning late) and sometimes the birds don't come back at all. Most maltese have never seen a Yelkouan Shearwater before and this behaviour explains why!
The team spent some anxious overnight stays on the cliffs hoping that they would be able to catch the bird again. It was a fantastic moment for the researchers from Heritage Malta and BirdLife when after three days after the tagging, the bird returned. Even better, the tag had worked and the crucial data could be downloaded. The celebrations were shared with the French LIFE team who have also been studying shearwaters and were visiting Malta to learn about how the Maltese team have been tagging the birds.
For those birds which had found a really deep burrow and hidden their chick out of site of our researchers, the shearwater team had an ingenious solution. Helped by the Maltese Civil Protection Unit, the team used a special piece of equipment called an endoscope. This device can see round corners and has a long tube to delve where the human eye can't see. It is usually used to detect illegal activities such as hidden drugs and explosives. Using the equipment for this rather novel purpose revealed many more nests than we would normally be able to see and confirmed the breeding success of several pairs.
So where does all of this leave our birds at Rdum tal-Madonna? Breeding success is higher this year and there are lots of parents feeding fat happy chicks. Around now the chicks will start exercising their wings. Then they'll be off and may not return to land for up to four years when they will return to breed. The adults will disperse to wherever it is that they spend the summer months before they come back in autumn. This year, we won't be able to follow them. But the team have plans for next year! We'll be fitting even smaller tracking devices to find out the birds' migratory pattern and by 2009 we hope to unravel this secret as well. While the Yelkouans are chasing the wind, the team will be chasing them (electronically at least) and the data we will collect will help to ensure that Yelkouan Shearwaters are able to raise their young on Malta's cliffs for many years to come.
The BirdLife Malta and BirdLife France (LPO) team on fieldwork
The Yelkouan Shearwater Project is a partnership iniative lead by BirdLife Malta of four government authorities (Heritage Malta, Malta Martime Authority, Malta Centre for Fisheries Sciences and the Armed Forces of Malta) and three conservation organisations (BirdLife Malta, SPEA - BirdLife Portugal and RSPB - BirdLife UK). It is part funded by the EU and receives financial contributions from HSBC and MEPA.
To learn more about the project, visit our website www.lifeshearwaterproject.org.mt or www.birdlifemalta.com. If you would like to volunteer for the project, contact the Project Manager Helen Raine on 21347644 or through e-mail firstname.lastname@example.org.